Refrigerators generally include a cabinet that defines a chilled chamber. The chilled chamber is commonly cooled with a sealed system having an evaporator. One problem frequently encountered with modem refrigerators is inefficient defrosting of the evaporator. For example, when the evaporator is active, frost can accumulate on the evaporator and thereby reduce efficiency of the evaporator. One effort to reduce or eliminate frost from the evaporator has been to utilize a heater, such as an electric heater, to heat the evaporator when the evaporator is not operating.
Defrosting the evaporator to completely remove frost buildup from the evaporator is difficult. Certain defrost cycles operate for a predetermined period of time. However, the predetermined period of time may be too short. Over time, ice can build up and accumulate on the evaporator, and the ice can eventually block air flow around the evaporator and negatively affect an efficiency of the evaporator. When the ice reaches a cooling fan, the ice can obstruct the fan's blades causing the fan to generate an irritating high pitch noise.
Accordingly, a method for operating a fan of a refrigerator appliance that assists with activating and/or terminating a defrost cycle of the refrigerator appliance would be useful. In addition, a method for operating a fan of a refrigerator appliance that assists with determining when ice obstructs the fan would be useful.